Abstract: An apparatus and method of operating a fuel vapor pressure management apparatus that includes a housing and a pressure operable device. The housing defines an interior chamber and includes first and second ports that communicate with the interior chamber. The pressure operable device separates the interior chamber into a first portion in fluid communication with the first port and a second portion in fluid communication with a second port. The pressure operable device includes a poppet movable along an axis and a seal adapted to cooperatively engage the poppet. A first arrangement of the pressure operable device occurs when there is a first negative pressure level at the first port relative to the second port, and the seal is in a first deformed configuration. A second arrangement of the pressure operable device permits a first fluid flow from the second port to the first port when the seal is in a second deformed configuration.

Abstract: A device for a fuel vapor pressure management apparatus of a fuel system supplying fuel to an internal combustion engine. The fuel vapor pressure management apparatus performs leak detection on a headspace of the fuel system, performs excess negative pressure relief of the headspace, and performs excess positive pressure relief of the headspace. The device includes a seal that is deformable between a substantially symmetrically deformed configuration, a generally asymmetrically deformed configuration, and an undeformed configuration. The seal is adapted to cooperatively engage a poppet such that a first arrangement that includes the seal in the substantially symmetrically deformed configuration and the poppet engaging the seal, a second arrangement that includes the seal in the generally asymmetrically deformed configuration and the poppet engaging the seal, and a third arrangement that includes the seal in an undeformed configuration and the poppet being disengaged from the seal.

Abstract: A fuel vapor treatment system is provided that diagnoses failure of the purge valve using one absolute pressure sensor. The fuel vapor treatment system includes a fuel tank, a canister, a drain cut valve, a purge valve, purge piping and a sensor. The canister adsorbs fuel vapor evaporated from the fuel tank. The drain cut valve controls the introduction of air into the canister. The purge valve is disposed between the canister and an intake passage into which fuel vapor flows from the canister. The purge piping communicates between the fuel tank and the intake passage via the canister. The sensor detects the absolute pressure inside the purge piping. The fuel vapor treatment system is further equipped with an atmospheric pressure setting device that sets the value detected by the sensor when the drain cut valve is open as the atmospheric pressure used for controlling the engine.

Abstract: An engine intake system has an imperforate walled pit disposed at an elevation vertically below a bottom wall in a main passageway that contains an entrance opening into the pit. Gaseous, heavier-than-air, hydrocarbon that is migrating upstream within the main intake passageway from an engine end of the main passageway along the bottom wall toward the entrance opening will fall through the entrance opening into the pit upon encountering the entrance opening. A medium, such as activated carbon, disposed within the interior space collects gaseous hydrocarbon that has fallen into the pit.

Abstract: An on-board fuel vapor recovery system draws vapors from a fuel tank, compresses the vapors, and then cools the compressed vapors to form a condensate liquid fuel which is stored in an auxiliary condensate tank for introduction to an engine for enhanced cold start operation.

Abstract: An outboard motor has an idle speed control in an induction and fuel injection system. The idle speed control controls the rate of flow of air through a bypass passage into the induction system to help improve engine performance. The bypass passage bypasses flow through the throttle body to increase the air flow while the throttle body is either closed or in a wide open position. Of course, the arrangement also can be used to increase the air flow in other orientations of the throttle valve. The bypass passage also is connected to a vent from a vapor separation tank such that vapor from the gas-filled vapor separation tank passes into the bypass air flow and is admitted into the intake system downstream of the throttle valve. The bypass air flow is subdivided between a number of the intake pipes. The bypass arrangement thus advantageously introduces a subdivided amount of ventilation air from the vapor separation tank into each of the plurality of combustion chambers formed within the engine.

Abstract: A filter blanket, for placement on an underside of a vehicle hood, and for use in recycling residual engine vapors from within an engine's intake system, includes a filter element and a cover. The filter element includes a plurality of wicking fibers. Each of the wicking fibers has an internal cavity formed therein, and a longitudinally extending slot formed therein extending from the internal cavity to the outer fiber surface. The filter blanket also includes a hydrocarbon-absorbing material disposed within the internal cavities of the fibers. The filter blanket may be used in conjunction with a routing duct, as part of a fuel vapor recycling system.

Abstract: An integrated pressure management system manages pressure and detects leaks in a fuel system. The integrated pressure management system also performs a leak diagnostic for the headspace in a fuel tank, a canister that collects volatile fuel vapors from the headspace, a purge valve, and all associated hoses and connections.

Abstract: A pressure operable device for an integrated pressure management apparatus. The pressure operable device includes a poppet moving between a first configuration permitting fluid communication between first and second ports of the integrated pressure management apparatus, and a second configuration preventing fluid communication between the first and second ports. A spring biases the poppet toward the second configuration, and a diaphragm operably engages the poppet to move the poppet toward the first configuration.

Abstract: An integrated pressure management system manages pressure and detects leaks in a fuel system. The integrated pressure management system also performs a leak diagnostic for the headspace in a fuel tank, a canister that collects volatile fuel vapors from the headspace, a purge valve, and all associated hoses and connections.

Abstract: The invention relates to a method for controlling the emission of fuel vapor from a fuel tank venting system in a preferably cylinder-specific intake duct of an internal, combustion engine, a control valve permitting the fuel vapor to reach the assigned intake duct synchronously with the intake cycle of the cylinder of the internal combustion engine, the opening time of the control valve being variable. Preferably, for controlling or metering larger amounts of fuel vapor, the opening time is placed in a range, in which there is a higher vacuum in the intake duct. On the other hand, for controlling or metering lesser amounts of fuel vapor, the opening time is placed in a range, in which there already is a lesser vacuum in the intake duct. The closing point of the control valve is also variable and this control valve is not opened, if there is excess pressure in the intake duct.

Abstract: A vapor removal fuel containment fuel tank for a vehicle includes a tank shell having a wall formed from a primary fuel containment layer. The fuel tank also includes a secondary fuel containment layer disposed adjacent the primary fuel containment layer to contain fuel therein. The fuel tank further includes a vapor removal system extending through the primary fuel containment layer to allow fuel vapors that build up between the primary fuel containment layer and secondary fuel containment layer to be removed from the fuel tank.

Abstract: A low-profile tank isolation valve mounts on a wall of a fuel tank to enclose an opening in the tank wall through which an inlet port of the valve is communicated to tank headspace. An electric actuator is selectively energized to selectively operate an armature to cause a closure to seat on, and unseat from, a valve seat. The armature is a cylindrical walled tube that is disposed within a central through-hole of the actuator and is selectively positioned along a straight axis coincident with the tube axis. An element that operatively relates the armature to the closure constrains vapor flow through the valve to pass through the armature tube when the closure is unseated. The seat, closure, and element are all disposed within the actuator through-hole.

Abstract: A gasoline vapor storage canister is employed to temporarily store hydrocarbon vapors vented from the gas tank in an automotive vehicle using an engine or fuel cell motive means which is fuelled at least in part from an on-board-the-vehicle, partial oxidation (POx) reactor for converting gasoline to a hydrogen-containing POx fuel. During cold start situations, gasoline vapor is purged from the storage canister to supply a stream of combustible fuel/air mixture to the POx reactor for ignition and heat up of the catalytic reactor to its operating temperature.

Abstract: A method for minimizing evaporative fuel emissions of a vehicle having an internal combustion engine, the engine having a combustion chamber, a corresponding fuel injector and a throttle valve assembly in cooperation with a corresponding intake manifold, the method including the step of storing fuel vapors that emanate from the engine to prevent “upstream” migration of the fuel vapors from the engine through the throttle valve assembly. The stored fuel vapors can then be released back into the engine for combustion thereby avoiding release into the atmosphere.

Abstract: A seal assembly for a fuel tank having a tank opening and a component disposed therein includes a seal adapted to be disposed between the component and a tank surface of the fuel tank. The seal assembly also includes an encapsulated studded ring assembly for attachment to the tank surface and adapted to be disposed about the tank opening. The seal assembly further includes a locking ring cooperating with the encapsulated studded ring assembly for engagement with the component to secure the component to the fuel tank and to seal the tank opening via the seal.

Abstract: An evaporative emission control system is provided wherein a differential pressure valve includes a diaphragm that separates a back pressure chamber and a tank chamber from each other, and has a communication hole formed therethrough. The differential pressure valve is placed in an open state in which the diaphragm is spaced apart from a valve seat, or a closed state in which the diaphragm rests on the valve seat. The differential pressure valve further includes a closure member for closing the communication hole when the differential pressure valve is placed in the closed state, and the communication hole communicates with the back pressure chamber and the tank chamber when the differential pressure valve is in the open state.

Abstract: An internal combustion engine is provided with a variable valve train capable of altering opening and closing timings and/or opening amounts of at least one of an intake valve and an exhaust valve of an internal combustion engine. The internal combustion engine is characterized in that the internal combustion engine is further provided with a negative pressure mechanism that operates using intake pipe negative pressure generated in an intake passage of the internal combustion engine, a throttle valve for adjusting the flow rate of intake air flowing through the intake passage, and negative pressure generating device that controls at least one of the variable valve train and the throttle valve to generate the intake pipe negative pressure, when the intake pipe negative pressure for operation of the negative pressure mechanism is insufficient.

Abstract: A fuel pump module for a fuel tank in a vehicle includes a reservoir adapted to be disposed in the fuel tank and a partition disposed in the reservoir to divide the reservoir into a fuel sensing chamber and a fuel storage chamber. The fuel pump module also includes a conduit conducting return fuel from an engine of the vehicle to the fuel storage chamber of the reservoir. The fuel pump module includes a fuel pump disposed in the reservoir and having an inlet disposed in the fuel sensing chamber and an outlet disposed in the fuel storage chamber. The fuel pump module further includes a fuel usage priority valve to allow fuel from the fuel storage chamber to flow to the fuel sensing chamber to provide the inlet of the fuel pump with fuel from the fuel storage chamber.

Abstract: An improved engine emission control for controlling both nitrous oxide emissions through an exhaust gas recirculation system and evaporative fuel emissions. These gases (exhaust and evaporated fuel) are mixed with the intake charge in a mixing chamber that surrounds the intake passage so as to insure good mixing at an upstream point removed from the combustion chambers so that a uniform mixture will be delivered to each chamber and there will be uniformity in the added mixture between the chambers.

Abstract: An emission control system includes a purge valve mounted to an air intake manifold. An external wall defines an internal manifold space for distributing induction flow that has entered the manifold to be directed to the engine cylinders. A substantially cup shaped purge valve mount preferably extends from the external wall. A snap attachment assembly mounts the purge valve assembly into the mount for ease of purge valve assembly mounting and removal. The snap attachment assemblies preferably align the purge valve assembly within the mount to assure that the exhaust port communicates through exhaust aperture. To install the purge valve assembly into the mount, the purge valve assembly need only be pressed into the mount until and attachment member encounters an associated lock.

Abstract: An evaporative fuel leakage preventing device is designed such that an adsorbent is disposed in an intake passage so as to adsorb evaporative fuel generated in the intake passage during stoppage of the engine and prevent evaporative fuel from being discharged to the atmosphere. The device prevents evaporative fuel that has been previously adsorbed by the adsorbent, and that is desorbed from the adsorbent due to the ambient temperature while the engine is not in operation, from being emitted to the atmosphere even when the engine is not in operation.

Abstract: A fuel assembly 10 which selectively receives volatile fuel 26 and which communicates the vapors to a carbon canister 42 for treatment prior to being released into the atmosphere or environment 38. The canister 42 is coupled to the fuel 26 by the use of various valves 30, 32, transducer 34, and conduits 35, 39, which are sealed from the environment 38.

Abstract: A method is presented for controlling fuel tank pressure in an internal combustion engine. The engine, the fuel tank and the carbon canister are connected in a three-way connection. The engine can be selectively isolated by a purge control valve, and the fuel tank can be selectively isolated by a fuel tank control valve. The operation of both valves is coordinated by an electronic engine controller. By isolating the fuel tank during the carbon canister purge, vapor spikes into the engine are eliminated, thus preventing engine stalls. Also, canister durability is improved by continuously storing and purging vapors in opposite directions.

Abstract: The object of this invention is to improve the safety of an engine by preventing fuel which might splash out of the fuel inlet on top of the fuel tank or drip onto the tank during fueling from coming in contact with the hot cylinder or any electrical components. Another object of this invention is to prevent vibration of the fuel tank and the noise which such vibration would cause. The fuel tank according to this invention has an upper and a lower portions joined by a flange, both of which are made from a resin material. The upper portion has a trapezoidal depression in its center which surrounds the fuel inlet and slopes downward toward one side of the tank. The overall surface of the upper portion is convex and also slopes downward toward the same side of the tank. A number of grooves on either side of the central depression run in the same direction and open onto the same side of the tank. The two halves of the tank are welded at the web of a ribbed flange which extends around the entire periphery.

Abstract: A fuel pump suctions fuel from a fuel tank and discharges it into a pressure tank. Then, the fuel pump suctions the fuel from the pressure tank and pressurizes it. Then, the fuel pump discharges the pressurized fuel toward an engine side through a fuel discharge pipeline. A pressure control valve is opened to communicate an inside of the fuel tank and an inside of the pressure tank when a pressure in the pressure tank becomes equal to or greater than a predetermined pressure. A canister receives activated carbons for absorbing vapor fuel from the fuel tank. A pressurizing pump suctions the vapor fuel from the canister and pressurizes it. The pressurized vapor fuel is then discharged from the pressurizing pump into the pressure tank, so that the vapor fuel is dissolved into the fuel in the pressure tank.

Abstract: An evaporative emission control system for an internal combustion engine isolates the fuel tank from the engine during purging of a carbon canister used to store fuel vapor drawn from the fuel tank during refueling. The flow of vapor from the tank to the canister is controlled by a main vapor control valve, and the flow of vapor from the canister to the engine is controlled by a purge valve. Pressure transducers are used to independently sense vapor pressure in the tank and in the canister. An electronic controller operates the valves based in part on the pressure information generated by the pressure transducers.

Abstract: A fuel supply system for a vehicle is provided with a fuel pump disposed in a fuel tank sitting astride a vehicle body frame. The fuel pump is disposed along a side surface of the fuel tank in a position opposed to a portion of the vehicle body frame. This fuel supply system for a vehicle provides a system in which a fuel pump can be disposed even in a fuel tank of a saddle-ridden vehicle with minimum modifications required in size and shape.

Abstract: An active bladder system and method for using same minimizes vapor formation in a fuel tank. A low-permeation, flexible conductive bladder (18) is contained within a fuel tank (12). The bladder (18) holds or contains the liquid fuel (25) in the fuel tank (12). The bladder (18) has air pressure applied to the outside of the bladder (18) to keep the bladder (18) against the fuel (25) to prevent vapor formation during engine running modes and diurnal cycles. A fuel delivery pump (23), external to the fuel tank, pressurizes the fuel to a desired pressure for use by an engine. The system is depressurized during refueling stages. Because vapor generation is minimized during running mode and diurnal cycles, no carbon canister or purge system is required by the present invention, resulting in cost savings and lower emissions levels. The present invention is compatible with conventional fueling infrastructures and may reduce fuel pump (23) current draw due to positive pressure on the bladder (18) during running modes.

Abstract: Fuel vapor is introduced into an intake passage of a direct fuel injection type engine by a fuel vapor purge apparatus. The intake passage is provided with an intake oxygen concentration sensor for detecting the amount of fuel vapor in intake air. An ECU corrects the amount of fuel injection from each direct fuel injection valve in accordance with the amount of fuel vapor detected, and changes the fuel injection starting timing and the fuel injection ending timing in accordance with the amount of fuel vapor.

Abstract: In order to regenerate an activated carbon filter which is seated in a tank vent line, during idling of the internal combustion engine the regeneration valve is brought into the maximum open position, and the throttle valve is simultaneously opened slightly. This produces a higher air mass flow in the intake tract of an internal combustion engine, and the proportion of hydrocarbons introduced by the regeneration remains constant. In order to keep the idling speed of the internal combustion engine constant, a torque reserve is built up, for example by adjusting the ignition angle.

Abstract: The pressure control valve is structured such that a first port is formed on one side of a casing, a second port is formed on the other side, and, in the casing, there are disposed not only a positive pressure valve which, when the pressure on the first port side becomes high, can be moved to the second port side to thereby communicate with the second port side, but also a negative pressure valve which, when the pressure on the first port side becomes low, can be moved to the first port side to thereby communicate with the second port side. In the pressure control valve, there is provided flow passage expanding means which, which the positive pressure valve has moved to the second port side beyond a given distance, allows the first port side to communicate with the second port side.

Abstract: In order to reduce a discharge amount of an evaporated fuel to the atmosphere and make it possible to manufacture an automobile in accordance with a module production, in a canister module, a fill check valve, a cut off valve, a positive and negative pressure check valve and the like are previously assembled in a module main body in an integral manner and the canister module is covered with a cover portion of a canister case having an absorbent storage chamber on an evaporated fuel outlet side and the cover portion is welded to a module main body so as to keep an airtight condition, thereby forming a passage portion surrounded by the cover portion and the module main body. Accordingly, a rubber hose is omitted and a transmitting amount of the evaporated fuel to the atmosphere is reduced.

Abstract: Evaporated fuel gas from a canister is introduced into an intake path of an internal combustion engine. A target air-fuel ratio is changed to a value on the fuel rich side during the introduction of purge gas in accordance with the purge gas concentration. This change will restrict the shift of the air-fuel ratio toward the lean side, allowing a catalyst to operate at high purification efficiency even during the introduction of purge gas. The change may be varied in accordance with the volume of the evaporated fuel gas or a ratio of the evaporated fuel gas to the fuel supplied to the engine.

Abstract: A fuel pump isolation assembly for a fuel pump of a vehicle includes a fuel pump and an isolation housing having a fuel pump cavity extending axially therethrough to receive the fuel pump. The fuel pump isolation assembly also includes a plurality of flex arms extending from the isolation housing and into the fuel pump cavity to engage the fuel pump and allow radial movement of the fuel pump during its operation.

Abstract: A diaphragm for an integrated pressure management system manages pressure and detects leaks in a fuel system. The integrated pressure management system also performs a leak diagnostic for the headspace in a fuel tank, a canister that collects volatile fuel vapors from the headspace, a purge valve, and all associated hoses and connections.

Abstract: A tank-venting system includes an active charcoal filter (20), which is connected to a tank (10). An intake manifold (40) of an internal combustion engine is connected to a tank-venting valve (30). The active charcoal filter (20) stores fuel vaporized in the tank (10). When the tank-venting valve (30) is driven open by the control unit (60), air from the ambient is drawn by suction through the active charcoal filter (20) and the fuel stored therein is released to the inducted air. A pump (50) is provided for checking the tightness of the tank-venting system and is connected to the control unit (60). A switchover valve (70) is connected downstream of the pump (50). A reference leak (81) is arranged in parallel to the switchover valve (70). A throughflow sensor (90) and a temperature sensor (91) are connected forward of the pump (50) which detect the scavenging air quantity, which is used to scavenge the active charcoal filter (20), as well as the intake air temperature.

Abstract: A supercharged combustion engine including a cylinder block (1), a cylinder head (2) and a crankcase (3) containing oil, an induction air conduit (19, 21, 24) communicating with intake conduits (9) in the cylinder head. The induction air conduit is connected to a supercharging unit (23) and is provided with a throttle valve (26) downstream of the supercharging unit. A first evacuation conduit (40, 42) connects the crankcase, via a pressure regulator (45), to the induction air conduit (19) at a point downstream of the throttle valve for evacuation of blow-by gases from the crankcase. A second evacuation conduit (40, 43) connects the crankcase with the induction air conduit (24) at a point on the intake side of the supercharging unit.

Abstract: A fuel system, a method for operating the fuel system and a method for operating an engine which is supplied by the fuel system each comprise: (1) a fuel tank; (2) a fuel vapor tank in fluid communication with the fuel tank by means of a first fuel vapor conduit; and (3) an engine in fluid communication with the fuel vapor tank by means of a second fuel vapor conduit. Within each of the fuel system and the two methods, there is captured, contained and compressed within the fuel vapor tank a fuel vapor extracted from the fuel tank when either: (1) refueling the fuel tank whether or not the engine is operating; (2) when the engine is operating whether or not refueling the fuel tank; or (2) immediately after shutting down the engine after having operated the engine. The fuel vapor within the fuel vapor tank may then be employed alone for restarting the engine, in absence of liquid fuel from the fuel tank.

Abstract: A component mounting arrangement for an engine includes an improved construction that can allow components such as a wire harness and/or fluid conduits to be neatly arranged around the engine. The engine includes a valve actuation mechanism and a drive mechanism through which a crankshaft drives the valve actuation mechanism. The drive mechanism is disposed generally above a cylinder block and a cylinder head assembly. At least one guide member is arranged to guide the wire harness and/or the fluid conduit across the engine. The guide member traverses above the drive mechanism.

Abstract: A fuel vapor treatment or recovery system for an automotive internal combustion engine. The system comprises a canister containing a fuel vapor adsorbing material. A membrane separation module is provided to be connected to the canister and including a separation membrane for separating a mixture gas into an air-rich component and a fuel vapor-rich component. The separation membrane has an air-selective permeability so that the air-rich component is be able to pass through the separation membrane, the mixture gas containing air and fuel vapor. Additionally, a gas transporting device is provided to be connected to the canister, for causing purge gas to be introduced into the canister to purge fuel vapor from the fuel vapor adsorbing material and causing fuel vapor purged from the canister to be fed to the membrane separation module.

Abstract: A fuel delivery module for an automotive fuel delivery system includes a reservoir and a fuel pump. The fuel pump delivers fuel from the tank to the reservoir via a fuel tank inlet and reservoir outlet and from the reservoir to the engine via a reservoir inlet and engine outlet. The reservoir is formed with a plurality of contaminant traps for collecting contaminants contained in the fuel as the fuel is pumped through the reservoir such that the contaminants settle unto said contaminant traps thereby reducing the amount of contaminants entering the reservoir inlet.

Abstract: A system and method for indicating leakage from a contained volume for holding volatile liquid, such as from an evaporative emission space of an automotive vehicle fuel system. A reciprocating pump operates to build pressure in the space toward a nominal test pressure. As the pressure is building toward nominal test pressure, but before nominal test pressure is achieved, measurements of substantially the amount of time required for the pump to execute a defined downstroke are repeatedly taken. These measurements may be referred to as pulse durations, and they are processed by an algorithm to detect when the rate of change in pulse duration changes from positive to negative, thereby defining the inflection point of a logistic curve. Subsequent measurements are taken and processed to predict a value at which substantially the pulse duration will ultimately stabilize. The predicted value is processed to indicate any leakage.

Abstract: An electronic onboard refueling vapor recovery (ORVR) system including an electrically operated ORVR valve that selectively opens and closes a fuel vapor path between a fuel tank and a collection canister. An electronic control circuit generates control signals to selectively open and close the ORVR valve. The electronic control circuit receives one or more inputs from one or a plurality of sensors and evaluates the one or more inputs to determine whether to activate the ORVR valve. The sensor inputs include at least a sensor indicating fuel is being introduced into the filler neck and may also include at least a sensor indicating a fuel level within the tank.

Abstract: An evaporating fuel processing apparatus of an internal combustion engine is disclosed, which can reliably determine the presence or absence of leakage even if stopping and restarting operations of the internal combustion engine are alternately repeated.

Abstract: A fuel delivery system for a boat having an internal combustion engine is provided. The system provides a source of fuel. A fuel supply conduit is connected to the source of fuel to deliver fuel to the engine. A fuel impermeable housing has one end coupled to the source of fuel and defines a passageway that receives the fuel supply conduit interiorly of the boat. The passageway is hermetically sealed relative to the interior of the boat and provides a return path into the fuel source to any fuel that may spill in the passageway.

Abstract: An evaporative emissions canister includes a housing containing a hydrocarbon adsorbing material, such as carbon. The canister may be configured to such that a portion acts as a buffer canister of such that the entire canister is used to adsorb hydrocarbon emissions. The canister housing is generally cylindrical with a reduced cross-sectional area portion and is configured in a manner to allow flow along a relatively straight line.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

Abstract: At the time of a stop of an engine, a diagnostic control unit shuts off a purge line with a purge control valve and an atmospheric port of a canister with a drain cut valve, and thereby holds an evaporative emission control circuit inclusive of a fuel tank and the canister in a state of a closed space during an off period of the engine. At the time of a next start of the engine, the diagnostic control unit measures a pressure in the closed circuit with a pressure sensor and checks a pressure decrease due to condensation of fuel vapors in the closed circuit to determine the existence or nonexistence of leakage.

Abstract: Apparatus is disclosed for venting a fuel tank including a canister containing an absorbent for fuel fumes, a sensor for detecting the filling of the fuel tank and emitting a signal based thereon, a first connection line for connecting the canister with the fuel tank and having a sufficient size to permit the free flow of gases from the fuel tank during filling of the fuel tank, the first connection line including a first valve operable between an open position and a closed position, the first valve normally being in the closed position and being actuatable into the open position by the signal thereby permitting the free flow of gas from the fuel tank through the first connection line during filling, a second connection line for connecting the canister with the fuel tank and connected to the first connection line between the first valve and the canister, the second connection line including a second valve including at least one restrictor for substantially limiting the flow of gases therethrough as compared t